An outer joint member of a constant velocity universal joint comprises, for example, a mouth section, and a stem section protruded from a bottom wall of the mouth section. Further, examples of the stem sections include a stem section provided with an oil seal fit portion. As described in Patent Literature 1 and the like, there is proposed a method of finishing an outer surface of this oil seal fit portion (that is, sealing surface) using an elastic grindstone.
That is, Patent Literature 1 describes the method of first performing turning using the turning tool, and then polishing the turned surface using the elastic grindstone for removing the turning lead marks.